This Program Project Grant proposes to extend our studies of low level lead exposure in children and experimental animals to address the following questions: 1) Does prenatal exposure to lead affect outcome at birth and later in life? 2) Does lead exposure have long delayed effects related to aging or late neurologic disease? 3) Does chelation prevent demonstrated changes in synaptic maturity and dendritic complexity? Epidemiologic studies of gravid women and their offspring in which lead is the risk factor will conducted, treating birth outcome and later development as outcome variables. Animal models of controlled lead exposure will be employed to test the same hypotheses under experimental conditions. Animals will be given controlled amounts of lead at varied periods of gestation, and offspring studied for ultrastructural changes in brain, distribution of lead by radiosotopes, and behavioral change by quantitative techniques. The effects of chelation on outcome will also be studied.